How to select particular edges with a python script?
Armed with the extra information consider:

import bpy, bmesh

me = bpy.context.object.data

bm = bmesh.new()
bm.from_mesh(me)

EPSILON = 1.0e-5

for vert in bm.verts:
    if -EPSILON &lt;= vert.co.x &lt;= EPSILON:
        vert.select = True

bm.to_mesh(me)
bm.free()


Some clarification perhaps:

EPSILON represents a value that is close to 0. If you've ever inspected coordinates closely in Blender you will find a cut off point maybe at around 6 or 7 digits after the decimal where you start to encounter artefacts in the representation of that float. Because 0 and 0.0000012312423 are not the same number you can't simply do a check for equality with 0, instead you might check is the x component within EPSILON tolerance.

Here I make the significant digit 5 places after the decimal point, from practical experience i've found this to be sufficient.

&gt;&gt;&gt; 1.0e-5 == 0.00001
True


The above will select just the vertices, from that point selecting the edges shouldn't be too difficult. Here's a quick implementation

import bpy, bmesh

me = bpy.context.object.data

bm = bmesh.new()
bm.from_mesh(me)

EPSILON = 1.0e-5
for vert in bm.verts:
    if -EPSILON &lt;= vert.co.x &lt;= EPSILON:
        vert.select = True

for edge in bm.edges:
    if edge.verts[0].select and edge.verts[1].select:
        edge.select = True

bm.to_mesh(me)
bm.free()